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Diffstat (limited to 'modules/freetype2/src/smooth/ftsmooth.c')
| -rw-r--r-- | modules/freetype2/src/smooth/ftsmooth.c | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/modules/freetype2/src/smooth/ftsmooth.c b/modules/freetype2/src/smooth/ftsmooth.c new file mode 100644 index 0000000000..cdbc78c3e5 --- /dev/null +++ b/modules/freetype2/src/smooth/ftsmooth.c @@ -0,0 +1,595 @@ +/**************************************************************************** + * + * ftsmooth.c + * + * Anti-aliasing renderer interface (body). + * + * Copyright (C) 2000-2023 by + * David Turner, Robert Wilhelm, and Werner Lemberg. + * + * This file is part of the FreeType project, and may only be used, + * modified, and distributed under the terms of the FreeType project + * license, LICENSE.TXT. By continuing to use, modify, or distribute + * this file you indicate that you have read the license and + * understand and accept it fully. + * + */ + + +#include <freetype/internal/ftdebug.h> +#include <freetype/internal/ftobjs.h> +#include <freetype/ftoutln.h> +#include "ftsmooth.h" +#include "ftgrays.h" + +#include "ftsmerrs.h" + + + /* sets render-specific mode */ + static FT_Error + ft_smooth_set_mode( FT_Renderer render, + FT_ULong mode_tag, + FT_Pointer data ) + { + /* we simply pass it to the raster */ + return render->clazz->raster_class->raster_set_mode( render->raster, + mode_tag, + data ); + } + + /* transform a given glyph image */ + static FT_Error + ft_smooth_transform( FT_Renderer render, + FT_GlyphSlot slot, + const FT_Matrix* matrix, + const FT_Vector* delta ) + { + FT_Error error = FT_Err_Ok; + + + if ( slot->format != render->glyph_format ) + { + error = FT_THROW( Invalid_Argument ); + goto Exit; + } + + if ( matrix ) + FT_Outline_Transform( &slot->outline, matrix ); + + if ( delta ) + FT_Outline_Translate( &slot->outline, delta->x, delta->y ); + + Exit: + return error; + } + + + /* return the glyph's control box */ + static void + ft_smooth_get_cbox( FT_Renderer render, + FT_GlyphSlot slot, + FT_BBox* cbox ) + { + FT_ZERO( cbox ); + + if ( slot->format == render->glyph_format ) + FT_Outline_Get_CBox( &slot->outline, cbox ); + } + + typedef struct TOrigin_ + { + unsigned char* origin; /* pixmap origin at the bottom-left */ + int pitch; /* pitch to go down one row */ + + } TOrigin; + +#ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING + + /* initialize renderer -- init its raster */ + static FT_Error + ft_smooth_init( FT_Renderer render ) + { + FT_Vector* sub = render->root.library->lcd_geometry; + + + /* set up default subpixel geometry for striped RGB panels. */ + sub[0].x = -21; + sub[0].y = 0; + sub[1].x = 0; + sub[1].y = 0; + sub[2].x = 21; + sub[2].y = 0; + + render->clazz->raster_class->raster_reset( render->raster, NULL, 0 ); + + return 0; + } + + + /* This function writes every third byte in direct rendering mode */ + static void + ft_smooth_lcd_spans( int y, + int count, + const FT_Span* spans, + TOrigin* target ) + { + unsigned char* dst_line = target->origin - y * target->pitch; + unsigned char* dst; + unsigned short w; + + + for ( ; count--; spans++ ) + for ( dst = dst_line + spans->x * 3, w = spans->len; w--; dst += 3 ) + *dst = spans->coverage; + } + + + static FT_Error + ft_smooth_raster_lcd( FT_Renderer render, + FT_Outline* outline, + FT_Bitmap* bitmap ) + { + FT_Error error = FT_Err_Ok; + FT_Vector* sub = render->root.library->lcd_geometry; + FT_Pos x, y; + + FT_Raster_Params params; + TOrigin target; + + + /* Render 3 separate coverage bitmaps, shifting the outline. */ + /* Set up direct rendering to record them on each third byte. */ + params.source = outline; + params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT; + params.gray_spans = (FT_SpanFunc)ft_smooth_lcd_spans; + params.user = ⌖ + + params.clip_box.xMin = 0; + params.clip_box.yMin = 0; + params.clip_box.xMax = bitmap->width; + params.clip_box.yMax = bitmap->rows; + + if ( bitmap->pitch < 0 ) + target.origin = bitmap->buffer; + else + target.origin = bitmap->buffer + + ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch; + + target.pitch = bitmap->pitch; + + FT_Outline_Translate( outline, + -sub[0].x, + -sub[0].y ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[0].x; + y = sub[0].y; + if ( error ) + goto Exit; + + target.origin++; + FT_Outline_Translate( outline, + sub[0].x - sub[1].x, + sub[0].y - sub[1].y ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[1].x; + y = sub[1].y; + if ( error ) + goto Exit; + + target.origin++; + FT_Outline_Translate( outline, + sub[1].x - sub[2].x, + sub[1].y - sub[2].y ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[2].x; + y = sub[2].y; + + Exit: + FT_Outline_Translate( outline, x, y ); + + return error; + } + + + static FT_Error + ft_smooth_raster_lcdv( FT_Renderer render, + FT_Outline* outline, + FT_Bitmap* bitmap ) + { + FT_Error error = FT_Err_Ok; + int pitch = bitmap->pitch; + FT_Vector* sub = render->root.library->lcd_geometry; + FT_Pos x, y; + + FT_Raster_Params params; + + + params.target = bitmap; + params.source = outline; + params.flags = FT_RASTER_FLAG_AA; + + /* Render 3 separate coverage bitmaps, shifting the outline. */ + /* Notice that the subpixel geometry vectors are rotated. */ + /* Triple the pitch to render on each third row. */ + bitmap->pitch *= 3; + bitmap->rows /= 3; + + FT_Outline_Translate( outline, + -sub[0].y, + sub[0].x ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[0].y; + y = -sub[0].x; + if ( error ) + goto Exit; + + bitmap->buffer += pitch; + FT_Outline_Translate( outline, + sub[0].y - sub[1].y, + sub[1].x - sub[0].x ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[1].y; + y = -sub[1].x; + bitmap->buffer -= pitch; + if ( error ) + goto Exit; + + bitmap->buffer += 2 * pitch; + FT_Outline_Translate( outline, + sub[1].y - sub[2].y, + sub[2].x - sub[1].x ); + error = render->raster_render( render->raster, ¶ms ); + x = sub[2].y; + y = -sub[2].x; + bitmap->buffer -= 2 * pitch; + + Exit: + FT_Outline_Translate( outline, x, y ); + + bitmap->pitch /= 3; + bitmap->rows *= 3; + + return error; + } + +#else /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ + + /* initialize renderer -- init its raster */ + static FT_Error + ft_smooth_init( FT_Renderer render ) + { + /* set up default LCD filtering */ + FT_Library_SetLcdFilter( render->root.library, FT_LCD_FILTER_DEFAULT ); + + render->clazz->raster_class->raster_reset( render->raster, NULL, 0 ); + + return 0; + } + + + static FT_Error + ft_smooth_raster_lcd( FT_Renderer render, + FT_Outline* outline, + FT_Bitmap* bitmap ) + { + FT_Error error = FT_Err_Ok; + FT_Vector* points = outline->points; + FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); + FT_Vector* vec; + + FT_Raster_Params params; + + + params.target = bitmap; + params.source = outline; + params.flags = FT_RASTER_FLAG_AA; + + /* implode outline */ + for ( vec = points; vec < points_end; vec++ ) + vec->x *= 3; + + /* render outline into the bitmap */ + error = render->raster_render( render->raster, ¶ms ); + + /* deflate outline */ + for ( vec = points; vec < points_end; vec++ ) + vec->x /= 3; + + return error; + } + + + static FT_Error + ft_smooth_raster_lcdv( FT_Renderer render, + FT_Outline* outline, + FT_Bitmap* bitmap ) + { + FT_Error error = FT_Err_Ok; + FT_Vector* points = outline->points; + FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); + FT_Vector* vec; + + FT_Raster_Params params; + + + params.target = bitmap; + params.source = outline; + params.flags = FT_RASTER_FLAG_AA; + + /* implode outline */ + for ( vec = points; vec < points_end; vec++ ) + vec->y *= 3; + + /* render outline into the bitmap */ + error = render->raster_render( render->raster, ¶ms ); + + /* deflate outline */ + for ( vec = points; vec < points_end; vec++ ) + vec->y /= 3; + + return error; + } + +#endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ + +/* Oversampling scale to be used in rendering overlaps */ +#define SCALE ( 1 << 2 ) + + /* This function averages inflated spans in direct rendering mode */ + static void + ft_smooth_overlap_spans( int y, + int count, + const FT_Span* spans, + TOrigin* target ) + { + unsigned char* dst = target->origin - ( y / SCALE ) * target->pitch; + unsigned short x; + unsigned int cover, sum; + + + /* When accumulating the oversampled spans we need to assure that */ + /* fully covered pixels are equal to 255 and do not overflow. */ + /* It is important that the SCALE is a power of 2, each subpixel */ + /* cover can also reach a power of 2 after rounding, and the total */ + /* is clamped to 255 when it adds up to 256. */ + for ( ; count--; spans++ ) + { + cover = ( spans->coverage + SCALE * SCALE / 2 ) / ( SCALE * SCALE ); + for ( x = 0; x < spans->len; x++ ) + { + sum = dst[( spans->x + x ) / SCALE] + cover; + dst[( spans->x + x ) / SCALE] = (unsigned char)( sum - ( sum >> 8 ) ); + } + } + } + + + static FT_Error + ft_smooth_raster_overlap( FT_Renderer render, + FT_Outline* outline, + FT_Bitmap* bitmap ) + { + FT_Error error = FT_Err_Ok; + FT_Vector* points = outline->points; + FT_Vector* points_end = FT_OFFSET( points, outline->n_points ); + FT_Vector* vec; + + FT_Raster_Params params; + TOrigin target; + + + /* Reject outlines that are too wide for 16-bit FT_Span. */ + /* Other limits are applied upstream with the same error code. */ + if ( bitmap->width * SCALE > 0x7FFF ) + return FT_THROW( Raster_Overflow ); + + /* Set up direct rendering to average oversampled spans. */ + params.source = outline; + params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT; + params.gray_spans = (FT_SpanFunc)ft_smooth_overlap_spans; + params.user = ⌖ + + params.clip_box.xMin = 0; + params.clip_box.yMin = 0; + params.clip_box.xMax = bitmap->width * SCALE; + params.clip_box.yMax = bitmap->rows * SCALE; + + if ( bitmap->pitch < 0 ) + target.origin = bitmap->buffer; + else + target.origin = bitmap->buffer + + ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch; + + target.pitch = bitmap->pitch; + + /* inflate outline */ + for ( vec = points; vec < points_end; vec++ ) + { + vec->x *= SCALE; + vec->y *= SCALE; + } + + /* render outline into the bitmap */ + error = render->raster_render( render->raster, ¶ms ); + + /* deflate outline */ + for ( vec = points; vec < points_end; vec++ ) + { + vec->x /= SCALE; + vec->y /= SCALE; + } + + return error; + } + +#undef SCALE + + static FT_Error + ft_smooth_render( FT_Renderer render, + FT_GlyphSlot slot, + FT_Render_Mode mode, + const FT_Vector* origin ) + { + FT_Error error = FT_Err_Ok; + FT_Outline* outline = &slot->outline; + FT_Bitmap* bitmap = &slot->bitmap; + FT_Memory memory = render->root.memory; + FT_Pos x_shift = 0; + FT_Pos y_shift = 0; + + + /* check glyph image format */ + if ( slot->format != render->glyph_format ) + { + error = FT_THROW( Invalid_Argument ); + goto Exit; + } + + /* check mode */ + if ( mode != FT_RENDER_MODE_NORMAL && + mode != FT_RENDER_MODE_LIGHT && + mode != FT_RENDER_MODE_LCD && + mode != FT_RENDER_MODE_LCD_V ) + { + error = FT_THROW( Cannot_Render_Glyph ); + goto Exit; + } + + /* release old bitmap buffer */ + if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) + { + FT_FREE( bitmap->buffer ); + slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP; + } + + if ( ft_glyphslot_preset_bitmap( slot, mode, origin ) ) + { + error = FT_THROW( Raster_Overflow ); + goto Exit; + } + + if ( !bitmap->rows || !bitmap->pitch ) + goto Exit; + + /* allocate new one */ + if ( FT_ALLOC_MULT( bitmap->buffer, bitmap->rows, bitmap->pitch ) ) + goto Exit; + + slot->internal->flags |= FT_GLYPH_OWN_BITMAP; + + x_shift = 64 * -slot->bitmap_left; + y_shift = 64 * -slot->bitmap_top; + if ( bitmap->pixel_mode == FT_PIXEL_MODE_LCD_V ) + y_shift += 64 * (FT_Int)bitmap->rows / 3; + else + y_shift += 64 * (FT_Int)bitmap->rows; + + if ( origin ) + { + x_shift += origin->x; + y_shift += origin->y; + } + + /* translate outline to render it into the bitmap */ + if ( x_shift || y_shift ) + FT_Outline_Translate( outline, x_shift, y_shift ); + + if ( mode == FT_RENDER_MODE_NORMAL || + mode == FT_RENDER_MODE_LIGHT ) + { + if ( outline->flags & FT_OUTLINE_OVERLAP ) + error = ft_smooth_raster_overlap( render, outline, bitmap ); + else + { + FT_Raster_Params params; + + + params.target = bitmap; + params.source = outline; + params.flags = FT_RASTER_FLAG_AA; + + error = render->raster_render( render->raster, ¶ms ); + } + } + else + { + if ( mode == FT_RENDER_MODE_LCD ) + error = ft_smooth_raster_lcd ( render, outline, bitmap ); + else if ( mode == FT_RENDER_MODE_LCD_V ) + error = ft_smooth_raster_lcdv( render, outline, bitmap ); + +#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING + + /* finally apply filtering */ + { + FT_Byte* lcd_weights; + FT_Bitmap_LcdFilterFunc lcd_filter_func; + + + /* Per-face LCD filtering takes priority if set up. */ + if ( slot->face && slot->face->internal->lcd_filter_func ) + { + lcd_weights = slot->face->internal->lcd_weights; + lcd_filter_func = slot->face->internal->lcd_filter_func; + } + else + { + lcd_weights = slot->library->lcd_weights; + lcd_filter_func = slot->library->lcd_filter_func; + } + + if ( lcd_filter_func ) + lcd_filter_func( bitmap, lcd_weights ); + } + +#endif /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */ + + } + + Exit: + if ( !error ) + { + /* everything is fine; the glyph is now officially a bitmap */ + slot->format = FT_GLYPH_FORMAT_BITMAP; + } + else if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) + { + FT_FREE( bitmap->buffer ); + slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP; + } + + if ( x_shift || y_shift ) + FT_Outline_Translate( outline, -x_shift, -y_shift ); + + return error; + } + + + FT_DEFINE_RENDERER( + ft_smooth_renderer_class, + + FT_MODULE_RENDERER, + sizeof ( FT_RendererRec ), + + "smooth", + 0x10000L, + 0x20000L, + + NULL, /* module specific interface */ + + (FT_Module_Constructor)ft_smooth_init, /* module_init */ + (FT_Module_Destructor) NULL, /* module_done */ + (FT_Module_Requester) NULL, /* get_interface */ + + FT_GLYPH_FORMAT_OUTLINE, + + (FT_Renderer_RenderFunc) ft_smooth_render, /* render_glyph */ + (FT_Renderer_TransformFunc)ft_smooth_transform, /* transform_glyph */ + (FT_Renderer_GetCBoxFunc) ft_smooth_get_cbox, /* get_glyph_cbox */ + (FT_Renderer_SetModeFunc) ft_smooth_set_mode, /* set_mode */ + + (FT_Raster_Funcs*)&ft_grays_raster /* raster_class */ + ) + + +/* END */ |